Machine for finishing parts

ABSTRACT

A machine for finishing parts, such as welding tips, is disclosed. A driven spindle and cutting tool attached to the spindle are carried by a support over a work table which receives individual parts. The spindle and cutting tool are movable from an upper position to a lower, finishing position against a part. A feeding mechanism below the work table transfers the parts sequentially to a chucking mechanism which retains a part in a fixed finishing position beneath the cutting tool. A chute transfers finished parts away from the machine. A fluid control system is provided for automatic, sequential operation of the feeding and chucking mechanisms.

United States Patent r191 King Jan. 22, 1974 MACHINE FOR FINISHING PARTSPrimary Examiner-Francis S. Husar Inventor: gp eg p Attorney, Agent, orF1rmCarl Schaffer et 3].

Erie, Mich.'48l33 22 Filed: Jan. 13, 1972 [57] fBSTRACT A machme forfimshmg parts, such as weldmg tips, is PP 217,568 disclosed. A drivenspindle and cutting tool attached to the spindle are carried by asupport over a work 52 us. c1. 82/1 B, 82/2.7, 408/68, table whichreceives individual P The spindle and 403/69 cutting tool are movablefrom an upper position to a 511 1111. c1 B23b 5/16, 82% 13/00 lower,finishing 1 against a A feeding [58] Field of Searh H 408/67 68, 6910/4, 9 mechanism below the work table transfers the parts 10/21 5- mn B2.7 sequentially to a chucking mechanism which retains a part in a fixedfinishing position beneath the cutting [56] References Cited tool. Achute transfers finished parts away from the machine. A fluid controlsystem is provided for auto- 35 089 Z T PATENTS 408/69 matic, sequentialoperation of the feeding and chuckeec er 1,219,803 3/1917 Brightman408/67 mg mechamsms' 5 Claims, 7 Drawing Figures flesh/00 PATENTED JAN 22 I974 sum 2 or 2 MACHINE FOR FINISHING PARTS BACKGROUND OF THEINVENTION Automatic welding machines, used in mass production sheetmetal forming operations, utilize numerous welding tips to effect spotwelds. These welding tips are generally conically shaped, hollow,non-ferrous bodies which are placed in or over electrode holders on awelding machine. The welding tips are placed in contact with the partsto be welded. The electrode is energized and a spot weld under thewelding tip results.

The end portion of the welding tip which contacts the welding materialis tapered to the precise desired size of the spot weld to be placed onthe sheet metal work. Continued operation of the welding machine inlarge production operations, such as automobile body plants, causesextreme corrosion andblunting of the welding tip. As the tip is blunted,the cross-sectional area of the spot weld becomes increasingly large,causing a resultant waste of welding material and undesired sloppy weldjoints.

It has beena common practice in assembly operations to discard erodedwelding tips. Because a large assembly operation requires hundreds ofthese tips during the assembly of sheet metal bodies, the practice ofdiscarding an eroded welding tip iscostly. The present inventionprovidesa means for restoring these welding tips to their originaldesired taper in a simple and inexpensive manner. The welding tiprestored by the machine of the present invention may be used severaltimes before replacement with a new tip is necessary.

SUMMARY OF THE INVENTION The invention comprises a machine for finishingparts such as welding tips. The machine comprises a frame and avertically extending support which carries a driven spindle and a shapedcutting tool attached to the spindle over a work table. The spindle isconnected to the support for movement from an upper position to alowerfinishing position against the workpiece. An inclined magazinebelow the table conveys the parts by gravity against an abutment above afeeding rod. The feeding rod elevates the workpiece through a hole inthe table to a chucking mechanism in a finishing position below thecutting tool. Elevation of the feeding rod causes actuation of thechucking mechanism which engages and retains the workpiece. The feedingrod then retracts below the magazine. The driven spindle is lowered toits finishing position which is set at a predetermined height by anadjustable stop mechanism. The part is finished by the shaped cuttingtool, and then released by the chucking mechanism. The released partthen falls by gravity through the hole in the table and down an ejectorchute pivotally attached to the frame for movement from under the holewhen the feeding rod is elevated. A fluid driven control mechanismprovides sequential automatic operation of the feeding and chuckingmechanisms.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational view of thefinishing machine of the present invention;

FIG. 2 is a perspective view of an eroded welding tip to be finished bythe machine of the present invention;

FIG. 3 is a cross-sectional view of a welding tip being finished by themachine of FIG. 1',

FIG. 4 is a detail view .of a chucking mechanism of the machine of thepresent invention taken along line 4-4 of FIG. 1; I

FIG. 5 is a detail view of the machine of the present invention, showingdetails of the feeding rod and ejector chute on an enlarged scale;

FIG. 6 is the same view as FIG. 5 except with an ejector chute inposition for receiving a finished welding tip; and

FIG. 7 is a schematic view of the fluid control system of the presentinvention.

DESCRIPTION OF THE PREFERRED- EMBODIMENT Referring first to FIG. 1, amachine 10 for finishing welding tips 11 according to the presentinvention is shown. The machine 10 generally comprises a magazine 12 forserially advancing the welding tips 11; a feeding mechanism 13 forlifting a single welding tip 11 from the magazine 12 to a finishingposition A on a woflt table 14; a chucking mechanism 15. for retainingthat tip 11 in the finishing position A; a driven cutting mechanism 16which is movable from an upper position to a cutting position againstthe chucked welding tip 11; an ejector chute 17 for delivering thefinished welding tip away from the machine 11 to a receivingcontainertnot shown); and a control mechanism 19 (shown schematically inFIG". 7) for sequentially operating the feeding and chucking mechanisms.The machine 10 is supported by a vertical frame 19 connected 1 td a base20 which is secured to a floor by bolts 21. The

components connected to the frame comprise:

The magazine 12 Referring to FIG. 1, the magazine 12 comprises aninclined, grooved track 22 connected to the frame 19 at an upper end bybrackets 23 and at a lower end by a guide bearing 24. An adjustableabutment 25 comprising a set screw 26 is threadably attached to a flange27 on the guide bearing 24 across the downward-most end of the track 22.The track 22 is inclined at a sufficient angle to advance individualwelding tips placed therein by gravity against the-abutment 25.

The feeding mechanism 13 A cylinder 28 is connected below the guidebearing 24. A piston 29 is movable within the cylinder 28, throughactuation of a source of fluid pressure from a retracted position to anextended position. A feeding rod 30, connected to an upper side of thepiston 29, extends vertically from the cylinder 28 into and through theguide bearing 24 supporting the lower end of the inclined magazine l2.Adjustment of the set screw 26 of the abutment 25 locates an advancedwelding tip 11 in axial alignment with the feeding rod 30. A taper 31 isprovided on the feeding rod 30 to seat within the hollow welding tip 11.As is shown in FIGS. 5 and 6, movement of the piston 29 toward itsextended position raises the feeding rod 30 into communication with anadvanced welding tip 11, vertically transporting that welding tip 11from the magazine 12 to the finishing position A on the work table 14.

Referring to FIG. 1, a 'cam rod 32 connected to a lower side of thepiston 29 extends downwardly through the cylinder 28. A cam plate 33 isthreadably attached for axial adjustment along the cam rod 32. The camplate 33 strikes the cylinder 28 when the piston is moved vertically toits extended position, thus limiting the travel of the feeding rod 30.Upward and downward adjustment of the cam plate 33 thus provides meansof adjusting the desired vertical location of the finishing position Aof the welding tip 11. As will be discussed below the cam plate alsostrikes a limit switch 34 which actuates the chucking mechanism 15.

The chucking mechanism Referring to FIG. 4, the chucking mechanism 15comprises a fixed jaw 36 and an opposed, driven jaw 37 movable to aclosed position within flanged tracks 38 secured to the work table 14. Ahole 39 in the work table 14 is located between the flanged tracks 38 inaxial alignment with the feeding rod 30. The jaws 36 and 37, in theclosed position, define an annular socket 40 for receiving a welding tip11 placed therebetween.

The fixed jaw 36 is adjustable within the flanged tracks 38 by means ofa set screw 41 threaded to a plate 42 connected to the table 14.Adjustment of the fixed jaw 36 brings the annular socket 40 intoalignment with the hole 39. The driven jaw 37 is movable toward and awayfrom the fixedjaw 36 by a drive rod 43 connected to a fluid piston 44within a cylinder 45. Introduction of fluid under pressure to one sideof the piston 44 moves the driven jaw 37 to the closed position;introduction of fluid on the opposite side of the piston 44 opens thedriven jaw 37.

When a welding tip 11, carried on the feeding rod 30, is raised throughthe hole 39 to the finishing position A, the driven jaw 37 moves to theclosed position, engaging the welding tip 11 within the socket 40. Thewelding tip 11 is retained within the socket 40 for finishing by thecutting mechanism 16.

The cutting mechanism 16 Referring to FIG. 1, the cutting mechanismcomprises an electric motor 47 connected to a vertical support 48 whichextends from the frame 19. The electric motor 47 drives a spindle 49over the work table 14. The spindle 49 is in engagement with a crankhandle 50 for movement from an upper position to a cutting positionadjacent the finishing position A of the chucked welding tip 11.

A shaped cutting tool 51 of any suitable hard machining metal isconnected to the spindle 49. As shown in F103, the cutting tool of thepresent embodiment comprises a horizontal cutting surface h, an angularcutting surface a, and a vertical cutting surface v. Movement of therotating spindle 49 into the cutting position carries the cutting tool51 into contact with a chucked welding tip 11. The cutting surfaces h,a, v engage corresponding surfaces of the generally conically shapedwelding tip 11 to effect removal of the corroded areas shown as theytypically occur in FIG. 2.

An adjustable stop 52 engages a forked collar 55, carried on the spindle49, when the spindle is lowered to the cutting position. The stop 52comprises a set screw 53 threaded to a vertically extending shank 54.Movement of the forked collar 55 against the set screw 53 limits themaximum downward travel of the spindle 49. As will be apparent to thoseskilled in the art, adjustment of the set screw 53 therefore determinesthe location of the cutting position of the cutting tool 51.

Because the upper limit of travel of the feeding rod 30 and the lowerlimit of travel of the cutting tool 51 are positively determinable byadjustable stopping means already described, the amount of material tobe removed from a chucked welding tip 11 by the cutting tool 51 can beprecisely determined. Further, a welding tip which has become undersizedthrough repeated refinishing will be too short to be contacted by thecutting tool 51. Therefore an undersized welding tip which is no longersuitable for use can be easily detected by an operator of the machine10.

The ejector chute 17 Referring to FIGSv 5 and 6, the ejector chute 17comprises an inclined slide 56 having a floor 57 and sidewalls 58. Theejector chute 17 is pivotally attached by hinges 59 to the work table 14for movement into and out of a receiving position under a chuckedwelding tip 11. With the ejector chute 17 in a receiving position, afinished welding tip can be released by the chucking mechanism 15,permitting the welding tip 11 to fall through the hole 39 and down theslide 56 to a collecting container, (not shown). As the feeding rod 30carrying a next welding tip 11 moves upwardly from the magazine 12, thetip 11 is driven against the floor 57 of the ejector chute l7. Continuedmovement of the feeding rod 30 pivots the ejector chute 17 out ofposition to permit the carrying of the welding tip 11 to the chuckingmechanism. When the feeding rod 30 retracts, the ejector chute 17returns by gravity to its receiving position which is located by a fixedpart of the machine which stops further downward movement of the chute17, as seen in FIG. 6.

The control mechanism 18 Referring to FIG. 7, a schematic diagram of thecontrol mechanism 18 is shown. In the preferred embodiment of thepresent invention, the control system is pneumatic-operating from asource of pressurized air (not shown). The mechanism 18 comprises anactuator plunger 60 which intercepts the rotatable crank handle when thehandle is turned to return the spindle 49 to the upper position. Theplunger 60 is connected to an actuator valve 61 which is in an airpressure line. After the cutting tool 51 removes a predetermined desiredamount of corroded material from the chucked welding tip 11, and theforked collar strikes the set screw 53, as described, the crank handleis moved to raise the spindle 49. When the crank handle 50 strikes theplunger 60, the actuator valve 61 opens to (a) admit air under pressureto a pilot valve 62 which directs the air to one side of the chuckingcylinder 45 to open the chucking mechanism 15 and (b) to charge a timedbleed valve 63 which admits air to the feeding rod cylinder 28. Openingof the chucking mechanism 15 releases the finished welding tip 11 whichfalls down the ejector chute 17 as described. Air pressure to thefeeding rod cylinder 28 extends the feeding rod 30 to carry an advancedwelding tip 11 from the magazine 12 to the finishing position A asdescribed.

As the feeding rod 30 approaches the finishing position A, the cam plate33 connected to the feeding piston 29 strikes the limit switch 34 whichactuates a limit valve 64. Actuation of the limit valve 64 admits air toan opposite side of the chucking piston 45 to close the driven jaw 37against the fixed jaw 36, gripping a fed welding tip 11 within theannular socket 40.

After a predetermined period of time, the timed bleed valve 61 releasespressurized air from the feeding piston 29, causing the feeding rod 30to retract and placing the ejector chute 17 in a receiving position asdescribed above. The chucked welding tip 11 is then finished by thecutting tool 51 until the collar 55 again strikes the set screw 53. Thehandle 50 is then rotated to strike the plunger 61 to repeat the feedingand chucking cycles of the machine. Means are therefore provided forsequentially advancing, feeding, finishing, and ejecting welding tipparts from the finishing position.

Various modifications of the preferred embodiment described above willbe apparent to those skilled in the art and may be made withoutdeparting from the spirit and scope of the following claims.

What I claim is:

l. A machine for finishing parts comprising a frame, a verticallyextending support member connected to said frame, means connected tosaid support member for finishing individual parts, means for movingsaid finishing means from a first position to a second finishingposition against a part to be finished comprising a rotary drivenspindle, a shaped cutting tool connected to said spindle, gearing meansfor moving said spindle from its said first position to its saidfinishing position and stop means for adjustably locating said finishingposition, drive means connected to said support member for rotating saidfinishing means, a table connected to said frame for receiving one ofthe parts in a finishing position, means on said table for chucking apart in said finishing position, a magazine connected to said frame forconveying a part, feeding means reciprocatable from a lower positionbelow said magazine to an upper position adjacent said chucking meansfor feeding a part into said finishing position, means for ejecting afinished part from said machine, and cooperating control means forsequentially: (1 reciprocating said feeding means from its said lowerposition to its said upper position, (2) actuating said chucking means,(3). reciprocating said feeding means to its said lower position, (4)deactivating said chucking means, and (5) reactivating said feedingmeans.

2. A machine for finishing parts comprising a frame; means on said framefor sequentially feeding individual parts to be finished; meansresponsive to the completion of said sequential feeding for chucking thefed part; means on said frame for moving against and finishing thechucked part; means responsive to the completion of motion of saidfinishing means for releasing said chucking means; means on said framefor ejecting the released part from said machine; and means responsiveto the completion of motion of said finishing means for sequentiallyfeeding a next individual part to be finished.

3. A machine for finishing parts according to claim 1 wherein saidchucking means comprises a guide track connected to said table, anadjustable jaw member secured within one side of said guide track, and adriven jaw member movable within an opposite side of said guide trackwhereby closing of said movable jaw against said adjustable jaw engagesa work piece fed therebetween.

4. A machine for finishing parts according to claim 1, wherein saidfeeding means comprises a cylinder connected to said frame, a fluidactuated piston within said cylinder, a rod connected to said piston,and a seat on one end of said rod for retaining and transporting a partto be finished.

5. A machine for finishing parts according to claim 1, wherein saidcontrol means comprises: actuating means for initiating movement of saidfeeding means, and opening said chucking means; a contact surface on anend of said feeding rod, a limit switch engageable by said contactsurface for closing said chucking means; and deactuating means forreciprocating said feeding means into its said lower position.

1. A machine for finishing parts comprising a frame, a verticallyextending support member connected to said frame, means connected tosaid support member for finishing individual parts, means for movingsaid finishing means from a first position to a second finishingposition against a part to be finished comprising a rotary drivenspindle, a shaped cutting tool connected to said spindle, gearing meansfor moving said spindle from its said first position to its saidfinishing position and stop means for adjustably locating said finishingposition, drive means connected to said support member for rotating saidfinishing means, a table connected to said frame for receiving one ofthe parts in a finishing position, means on said table for chucking apart in said finishing position, a magazine connected to said frame forconveying a part, feeding means reciprocatable from a lower positionbelow said magazine to an upper position adjacent said chucking meansfor feeding a part into said finishing position, means for ejecting afinished part frOm said machine, and cooperating control means forsequentially: (1) reciprocating said feeding means from its said lowerposition to its said upper position, (2) actuating said chucking means,(3) reciprocating said feeding means to its said lower position, (4)deactivating said chucking means, and (5) reactivating said feedingmeans.
 2. A machine for finishing parts comprising a frame; means onsaid frame for sequentially feeding individual parts to be finished;means responsive to the completion of said sequential feeding forchucking the fed part; means on said frame for moving against andfinishing the chucked part; means responsive to the completion of motionof said finishing means for releasing said chucking means; means on saidframe for ejecting the released part from said machine; and meansresponsive to the completion of motion of said finishing means forsequentially feeding a next individual part to be finished.
 3. A machinefor finishing parts according to claim 1 wherein said chucking meanscomprises a guide track connected to said table, an adjustable jawmember secured within one side of said guide track, and a driven jawmember movable within an opposite side of said guide track wherebyclosing of said movable jaw against said adjustable jaw engages a workpiece fed therebetween.
 4. A machine for finishing parts according toclaim 1, wherein said feeding means comprises a cylinder connected tosaid frame, a fluid actuated piston within said cylinder, a rodconnected to said piston, and a seat on one end of said rod forretaining and transporting a part to be finished.
 5. A machine forfinishing parts according to claim 1, wherein said control meanscomprises: actuating means for initiating movement of said feedingmeans, and opening said chucking means; a contact surface on an end ofsaid feeding rod, a limit switch engageable by said contact surface forclosing said chucking means; and deactuating means for reciprocatingsaid feeding means into its said lower position.